Speed control switching mechanism



June 1, 1965 J, HAMMER 3,187,128

SPEED CONTROL SWITGHING MECHANISM Filed Aug. 9, 19.62 4 Sheets-Sheet 1 June 1, 1965 J. HAMMER SPEED CONTROL SWITCHING MECHANISM 4 Sheets-Sheet 2 Filed Aug. 9, 1962 J. HAMMER SPEED CONTROL SWITCHING MECHANISM June 1, 1965 4 Sheets-Sheet 3 Filed Aug. 9, 1962 June l, 1965 J. HAMMER 3,187,128

SPEED CONTROL SWITCHING MECHANISM Fild Aug. 9, 1962 4 Sheets-Sheet 4 United States Patent O 3,137,128 SPEED CONTROL SWITCHNG MECHANSM Josef Hammer, St. Annastrasse 1, Ehikon, Switzerland Filed Allg. 9, 1962, Ser. No. 215,924 Claims priority, application Switzerland, Aug. 12, 1961, 9,498/ 61 1 Claim. (Cl. 20S-61.45)

The present invention concerns an elevator safety device, more especially an arrangement for supervising the travelling speed of elevators.

Passenger elevators and goods elevators which may be entered have to be fitted with a safety catch which is released by a speed regulator when the normal travelling `speed has been exceeded by a certain value, at least during descent. If the safety catch is released then, at least in the case of a wedge safety catch, the cage is stopped with a considerable negative acceleration, which is unpleasant for the passengers.

It is therefore desirable in the case of minor excessive speeds to stop the elevator cage by means of a mechanical brake on the elevator motor, so that the speed regulator does not release the safety catch. The safety catch comes into effect only when the speed of the elevator cage increases further. This can be the case when there is a break in the .supporting cables or in the event of the cables slipping on the driving pulley. For this purpose it has already been proposed to use centrifugal switches on the elevator motor which, when the normal travelling speed is exceeded, interrupt the elevator control system and hence cause the mechanical brake to engage.

Any exceeding Vof the normal travelling speed necessitates the examination of the causes before the elevator can again be put into operation.

For this purpose the centrifugal switches are provided with a mechanical or electric locking system which keeps the elevator control system interrupted after the switches have responded until the locking has been released again by hand after inspecting the elevator.

Such centrifugal switches have several movable parts which are subjected to permanent wear. Owing to this wear the operating speed at which the switch responds can alter with time so that a periodical testing of the responding speed is necessary.

The object of the present invention is to provide an arrangement for supervising the travelling speed of elevators, which is distinguished by its particular simplicity and the parts of which execute no movement relative to one another in the region of normal speed. The arrangement in accordance with the invention for supervising the travelling speed of elevators having a cam regulator having at least one rocking lever, for releasing a safety catch is characterised by the feature that connected with one rocking lever there is a weight or mass body displaceably guided substantially tangential to the rocking lever movement and pressed against a fixed stop under action of an adjustable pressure application force, which body is adapted to co-operate in such a manner with a contact bridge of a contact in the circuit of the elevator that, when the mass body is lifted off the fixed stop, contact is interrupted, the mass of the body and the pressure application force being so selected that with a certain critical travelling speed the accelerating forces acting on the mass body lift the body off the fixed stop against the pressure application force, so that the control circuit is interrupted.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is an end elevation of a first embodiment in which the pressure application force is produced by a 3,187,128 Patented June l, 1965 ICC compression spring and in which the contact is fixedly disposed; q

FIG. 2 is a corresponding side elevation;

FiG. 3 is an end elevation of a second embodiment in which the contact is also arranged on the rocking lever; PIG. 4 is a side elevation corresponding to FIG. 3;

FlG. 5 is an end elevation of a third embodiment in which for obtaining a snap action the pressure application force is produced by means of a permanent magnet and in which the contact is also arranged on the rocking lever, the parts being shown in their normal position;

FiG. 6 is a side elevation corresponding to FIG. 5 but with the parts shown in their released position;

FG. 7 is a diagram of the forces acting when the lift construction of FlGS. 5 and 6 is stopped; and

FIG. 8 is a diagram of the acceleration forces acting on the mass body.

In FIGS. 1 and 2 the numeral 1 designates a cam regulator only partly shown, the structure and method of operation of which are assumed to be known. The regulator comprises a stand 1.1, a cam disc 1.2, and rocking lever 1.3 which has a boss 1.4 for mounting the axle 1.5 of a roller 1.6. A carrying stirrup 2 to which a U-profile 3 is fixed is rigidly screwed to the boss 1.4. The upper flange 3.1 of the U-profile 3 has a tapped hole 3.3 formed therein. A guide member 4 is threadedly engaged in the tapped hole 3.3 and locked in position by means of a nut 5. The guide member 4 acts as a guide for an actuating bolt 6 and as a support for a compression spring 7. A weight or mass body 8 is fixed on the actuating bolt 6. Adjusting the guide member 4 causes the pressure of the compression spring 7 against the weight body 8 to be adjusted. A contact is fixed to the stand 1.1 .of the cam regulator 1 by means of a stirrup 10. The weight body 3 screwed to the actuating bolt 6 is urged by action of its weight and the spring force of the compression spring 7 against the lower shank 3.2 of the U-profile. The rocking lever 1.3 is subjected to the action of a tension spring 1.7 which at the other end is fixed to the stand 1.1. This spring 1.7 tends to pull the roller 1.6 of the rocking lever 1.3 on to the cam disc 1.2, so that the rocking lever 1.3 is caused to execute an oscillating movement about its bearing 1.9 on rotation of the cam disc 1.2 driven by a regulating cable 1.3.

The arrangement shown in FIGS. 1 and 2 operates as follows: When the elevator is in motion, the cam disc 1.2 is driven and rotates at an angular speed proportional to the travelling speed of the lift. The rocking lever 1.3 thus executes the aforesaid rocking movement. The parts fixed to the carrying stirrup 2 are alternately accelerated upwards and decelerated again downwards in a substantially vertical direction. Consequently an acceleration force acts on the body 8 with a continuously varying magnitude and direction. The graph of the maximum of this acceleration force is thus a function of the travelling speed of the elevator cage. The dimensions of the cornpression spring 7 and of the body 8 have thus been so selected that, when a certain travelling speed has been exceeded, the acceleration force acting on the body 8 is greater than the sum of the weight of the body and of the spring force. At this travelling speed the weight body 8 is lifted away from the shank 3.2, so that the actuating bolt 6 lifts the contact bridge 9.1 of the contact 9 off the fixed contacts 9.2. Hence the control circuit of the lift is interrupted. The contact 9 can in known manner be so constructed that after it has been actuated by the actuating lever 6 it remains open having to be returned again by hand.

A further form of construction is evident from FIGS. 3 and 4, the same parts being provided with the same reference numeral.

A carrying stirrup 11 is screwed firmly to the boss 1.4.

aleman Its upper end is bent over at right angles and has a passage hole 11.1 for-med therein. A threaded pin 12 with a nut 13 and lock-nut 14 is inserted in the passage hole p 11.1. The carrying stirrup 11 has a stop 15 and a contact 16 fixed thereon. A weight or mass body 17 is fixed on the actuating bolt 13. The contact comprises a housing 16.1, ltwo fixed contacts 16.2 and a contact bridge 16.3.v For producing the contact pressure a spring 16.4 is provided. The actuating bolt 1S is guided in the housing 16.1. The upper end of a tension spring 19 is xed on the threaded pin 12 and the lower end to the body 17. The tension spring 19 draws the body 17 against the stop 15, which has a passage hole 15.1 for the tension spring 19 formed therein.

The method of operation of this design is the same in principle as in the above example. The Contact 15 however follows .the movement of the rocking lever which necessitates correspondingly displaceable supply leads to the iixed contacts 16.2. Furthermore, the weight of the body 17 herein acts against the spring force of thc tension spring 19, so that the body 17 is then lifted oil the iixed stop 15 or the contact bridge 16.3 off the xed contacts 16.2, when the sum of lthe acceleration force acting on the body 17 becomes greater than the spring force of the tension spring 19. The dimensions of the tension spring 19 and of the body 17 in turn are again selected in such a manner that the interruption takes place when a certain travelling speed of the lift is exceeded. The adjustment of the responding speed is effected by adjusting the nuts 13, 14 on the threaded pin 12. The contact 16 herein may also be so constructed that it remains open after the contact bridge has been lifted oil and having to be closed again by hand. Moreover the actuating bol-t 1S or the body 17 can be provided in known manner with a latching arrangement, so that these after initial actuation of the contact 16 remain in the actuating position and have to be returned again by hand.

A third embodiment of the arrangement is evident from FIGS. 5 and 6, in combination with the diagrams in FIGS.

7 and 8.

A carrying stirrup 2t) is rigidly screwed on to the boss 1.4. Its upper end is bent over at right angles and has a tapped hole 20.1 formed therein. An adjusting screw 21 is threadedly engaged in the tapped hole 20.1 by means of a nut 22. An armature core 23 and a contact 24 are iixed on the carrying stirrup 2t). The numeral 25 designates a permanent magnet, which is iixed on a square actuating bolt 26. The contact 24 comprises a housing 24.1, two iixed contacts 24.2 and a contact bridge 24.3. To produce the contact pressure a spring 24.4 is provided. The actuating bolt 26 is guided in the housing 24.1. The actuating bolt 26 with its upper end acts as a guide for a compression spring 2'7 acting on the permanent magnet 25. The compression spring 27 is supported at the top against the adjusting screw 21, which is provided with an extension Ifor guiding the compression spring 27. To understand the method of operation of this embodiment reference is iirst made to the diagrams. The air gap between the permanent magnet 25 and the armature core 23 is plotted on theabscissa 28 as shown in FIG. 7 and the forces onthe ordinate 29. The graph 30 .thus shows the Weight, the graph 31 the attracting force of the permanent magnet 25 and the graph 32 the force exerted by the compression spring 27 on the permanent magnet 25 in function of the air gap. The sum of these forces is illustrated by the graph 33. The air gap in the released position is designated by h.

They last described arrangement operates as follows: In the normal position, as shown in FliG. 5, the permanent magnet 25 adheres to the armature core 23 since as evident from HG. 7 with a Zero air gap, the attracting force (graph 31) exceeds the sum of weight (graph 3ft) and spring force (graph 32). The contact 24 is closed. When theV lift is in motion, the permanent magnet 25 has an acceleration force imparted thereto of varying amount and direction. The course of this acceleration force is shown in FIG. 8. In this case time is plotted on the abscissay 3d and the acceleration force on the ordinate 35. The graph 35 shows the course 0f the acceleration force engaging the permanent magnet 25 as a function of the time. lf the travelling speed reaches a value wherein the peak of the acceleration force is greater than the sum of the forces in accordance with graph 33 in FIG. 7 with Zero air gap, then thepermanent magnet 25 is detached from the armature core 23. As evident from FIG. 7, with increasing air gap the attracting force of the permanent magnet 25 is considerably reduced, the compressive force of the spring 27 however 'only slightly reduced, so that the permanent magnet 25 thereby assumes its end position shown in FIG. 6. The contact bridge 24.3 is thereby lifted off the contacts 24.2 and hence interrupts the elevator control system, whereby the mechanical brake comes into operation. After the time t the elevator stops (FlG. 8). As evident from FG. 7 in the air gap h the sum of the forces 32 and Sii exceeds the attractive force 31 of the permanent magnet 25, so that the contact remains open even during standstill. To operate theelevator it is necessary to close the air gap between armature core 23 and permanent magnet 25 by displacing the magnet 25. A similar effect would be obtained if the permanent magnet 25 were replaced by a non-magnetic weight or mass body, the latter however, being mounted in known manner on a knife edge under the action of a spring drawing it against the knife edge, would have a snap action.

lt should also be mentioned that in place of the rectilinear mobility of the weight or mass body, it could also be guided on a lever journalled to the rocking lever, so that, when the body is lifted off the fixed stop, it describes a circular path.

1 claim: 1

In combination with an elevator governor having a rotating cam responsive to the speed of travel of said elevator, and a cam follower mounted on one end of a lever pivoted about a point lying on a vertical line through the axis of said rotating cam, apparatus for operating the control contact of the electrical circuit of the elevator system comprising, a guide member disposed on said cam follower lever and movable therewith in a position substantially parallel to said vertical line, a weight slidably mounted in said guide member for reciprocal vertical movement relatively therewith, upper and Vlower stop means for limiting movementof said weight, means coacting with said weight in its upward movement for operating said control contact and adjustable spring means for normally urging said weight toward said lower stop, said weight being caused to act on said means for operating said control contact when the upward inertia caused by the rotation of said cam exceeds a predetermined speed.

References Cited by the Examiner UNlTED STATES PATENTS BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

